Urination isn’t one of the first words that leaps to mind when people think of civil rights, but activists in Mumbai have launched a new campaign called the “Right to Pee” to redress gross inequities in the allocation of public restrooms. In New Delhi, for example, according to the New York Times, there are more than 1,500 public restrooms for men and only 132 for women.

The burden of bad sanitation affects almost all poor people but it falls disproportionately on females: in urban areas, there is a fee for most public washrooms, but men can use urinals for free and they frequently relieve themselves in public when facilities are lacking. In rural areas, where most people have to defecate openly, women are often subject to harassment or assault when they relieve themselves. To avoid the need to urinate, they often withhold hydration, a practice resulting in high rates of urinary-tract infections, heatstroke and other health problems. And coping with menstruation in the absence of privacy, water or sanitary products can be a nightmare.

It’s hard to believe the scale of these problems in the 21st century. Yet the U.N. Millennium Development Goal — that the number of people without access to safe water and basic sanitation is to be reduced by half by year 2015 — has fallen “dangerously behind.” Around 2.5 billion people still use “unimproved” facilities, and 1 billion people lack access to toilets at all. We’re not talking about gleaming white bathroom stalls with energy-efficient hand dryers; one-sixth of all people defecate in open fields or in water used for bathing and drinking. In Africa, 60% of the population has no access to a proper toilet that separates human waste from other activities.

The impact of poor sanitation — and its economic consequences — is well-known. Diarrhea alone causes at least 800,000 child deaths per year in the developing world. Reductions in infant and maternal deaths are clear when access to sanitation and water is improved, and there are many “spillover” benefits of sanitation that extend beyond a reduction in fecal-borne disease. In other words, providing more toilets reduces illness and death from diseases that are not caused by a lack of toilets. This phenomenon (called the Wills-Reinecke multiplier) was first noticed when deaths from all infectious diseases, and not just typhoid, decreased after the water supply was improved in 19th century Massachusetts, and is probably explained by the body’s improved capacity to fight infection when it’s not under chronic attack by pathogens specifically in dirty water.

So why hasn’t this become an issue of global concern? Instead, between 1997 and 2008, the percentage of international aid that went to sanitation and water fell from 8% to 5%. Concerns over safe drinking water get much more attention, despite a recent World Bank study that found a more pronounced impact on health from building toilet infrastructure than from drinking-water improvements. Few people enjoy talking about bodily functions, and it’s hard for emerging economies to get excited about pit latrines and compost toilets when they’d rather showcase their shiny new buildings and high-speed trains. Feces and open sewers are a hard sell for donors too. There’s no pretty logo — no babbling brook or fresh water spring — for a toilet.

It’s not often that celebrities align themselves with unappealing causes, so it’s a great credit to Grammy Award–winning singer and producer Lenny Kravitz that he recently signed on as a UNICEF goodwill ambassador for water, sanitation and hygiene efforts. Let’s hope he has the fortitude to talk about more than just clean drinking water. He may find it embarrassing to shill for plumbing parts, but the only thing shameful about toilets is that more than a billion people lack them.